.. This work is licensed under a Creative Commons Attribution 4.0 International License.
.. http://creativecommons.org/licenses/by/4.0
-.. Copyright (C) 2021-2022 Nordix Foundation
+.. Copyright (C) 2021-2023 Nordix Foundation
+.. Modifications Copyright (C) 2023 TechMahindra Ltd
.. DO NOT CHANGE THIS LABEL FOR RELEASE NOTES - EVEN THOUGH IT GIVES A WARNING
-.. _design:
+.. _path:
CPS Path
=============
- String values must be wrapped in quotation marks ``"`` (U+0022) or apostrophes ``'`` (U+0027).
+- Quotations marks and apostrophes can be escaped by doubling them in their respective quotes, for example ``'CPS ''Path'' Query' -> CPS 'Path' Query``
- String comparisons are case sensitive.
-- List key-fields containing ``\`` or ``@[`` will not be processed correctly when being referenced with such key values in absolute or descendant paths. This means such entries will be omitted from any query result. See `CPS-500 <https://jira.onap.org/browse/CPS-500>`_ Special Character Limitations of cpsPath Queries
Query Syntax
============
-``( <absolute-path> | <descendant-path> ) [ <leaf-conditions> ] [ <text()-condition> ] [ <ancestor-axis> ]``
+``( <absolute-path> | <descendant-path> ) [ <leaf-conditions> ] [ <text()-condition> ] [ <contains()-condition> ] [ <ancestor-axis> ]``
Each CPS path expression need to start with an 'absolute' or 'descendant' xpath.
**Limitations**
- Absolute paths must start with the top element (data node) as per the model tree.
- Each list reference must include a valid instance reference to the key for that list. Except when it is the last element.
- - The Absolute path to list with integer key will not work. It needs to be surrounded with a single quote ([@code='1'])
- as if it is a string. This will be fixed in `CPS-961 <https://jira.onap.org/browse/CPS-961>`_
descendant-path
---------------
leaf-conditions
---------------
-**Syntax**: ``<xpath> '[' @<leaf-name1> '=' <leaf-value1> ( ' and ' @<leaf-name> '=' <leaf-value> )* ']'``
+**Syntax**: ``<xpath> '[' @<leaf-name1> '(=|>|<|>=|<=)' <leaf-value1> ( ' <and|or> ' @<leaf-name> '(=|>|<|>=|<=)' <leaf-value> )* ']'``
- ``xpath``: Absolute or descendant or xpath to the (list) node which elements will be queried.
- ``leaf-name``: The name of the leaf which value needs to be compared.
- ``leaf-value``: The required value of the leaf.
- ``//categories[@name="Kids"]``
- ``//categories[@name='Kids']``
- ``//categories[@code='1']/books/book[@title='Dune' and @price=5]``
+ - ``//categories[@code='1']/books/book[@title='xyz' or @price=15]``
+ - ``//categories[@code='1']/books/book[@title='xyz' or @price>20]``
+ - ``//categories[@code='1']/books/book[@title='Dune' and @price<=5]``
- ``//categories[@code=1]``
**Limitations**
- Only the last list or container can be queried leaf values. Any ancestor list will have to be referenced by its key name-value pair(s).
- - Multiple attributes can only be combined using ``and``. ``or`` and bracketing is not supported.
+ - When mixing ``and/or`` operators, ``and`` has precedence over ``or`` . So ``and`` operators get evaluated first.
+ - Bracketing is not supported.
+ - Leaf names are not validated so ``or`` operations with invalid leaf names will silently be ignored.
- Only leaves can be used, leaf-list are not supported.
- Only string and integer values are supported, boolean and float values are not supported.
+ - Using comparative operators with string values will lead to an error at runtime. This error can't be validated earlier as the datatype is unknown until the execution phase.
- The key should be supplied with correct data type for it to be queried from DB. In the last example above the attribute code is of type
Integer so the cps query will not work if the value is passed as string.
- eg: ``//categories[@code="1"]`` or ``//categories[@code='1']`` will not work because the key attribute code is treated a string.
+ e.g.: ``//categories[@code="1"]`` or ``//categories[@code='1']`` will not work because the key attribute code is treated a string.
**Notes**
- For performance reasons it does not make sense to query using key leaf as attribute. If the key value is known it is better to execute a get request with the complete xpath.
**Syntax**: ``<cps-path> ( '/' <leaf-name> '[text()=' <string-value> ']' )?``
- ``cps-path``: Any CPS path query.
- ``leaf-name``: The name of the leaf or leaf-list which value needs to be compared.
- - ``string-value``: The required value of the leaf or leaf-list element as a string wrapped in quotation marks (U+0022) or apostrophes (U+0027). This wil still match integer values.
+ - ``string-value``: The required value of the leaf or leaf-list element as a string wrapped in quotation marks (U+0022) or apostrophes (U+0027). This will still match integer values.
**Examples**
- ``//book/label[text()="classic"]``
- Since CPS cannot return individual leaves it will always return the container with all its leaves. Ancestor-axis can be used to specify a parent higher up the tree.
- When querying a leaf value (instead of leaf-list) it is better, more performant to use a text value condition use @<leaf-name> as described above.
+contains()-condition
+--------------------
+
+**Syntax**: ``<cps-path> '[' 'contains' '(' '<leaf-name>','<string-value>' ')' ']'?``
+ - ``cps-path``: Any CPS path query.
+ - ``leaf-name``: The name of the leaf which value needs to be compared.
+ - ``string-value``: The required value of the leaf element as a string wrapped in quotation marks (U+0022) or apostrophes (U+0027). This will still match integer values.
+
+**Examples**
+ - ``//categories[contains(@name,'Sci')]``
+ - ``//books[contains(@title,'Space')]``
+
+**Limitations**
+ - Only leaves can be used, leaf-list are not supported.
+ - Leaf names are not validated so ``contains() condition`` with invalid leaf names will silently be ignored.
+
+**Notes**
+ - contains condition is case sensitive.
+
ancestor-axis
-------------
Code Review / cps.git / blobdiff